In how many ways is the act of Baptism practised?

It may be performed by 1 sprinkling or 2 pouring water on the head or by 3 immersing in water either partially or 4 completely. Four. Count them. Four.

There is also something called "baptism by desire" and Mormons have "baptism by proxy". Also, baptism isn't practiced, it is performed.

Myanswer was 4 ...immersion submersion aspersions affusion

Timoteo, pedant! 😉

So along with immersion, sprinkling, and pouring there are at least three. I have heard of "casting", but haven't found any information on it.

(above quote per ee.umc.org)

The answer to the question is faulty by omission. The Methodist Church uses sprinkling or pouring: Our church has always offered to people being baptized and to the parents of infants the choice of sprinkling, pouring, or immersion. Sprinkling is a common practice, but the person being baptized (or their sponsors) can choose the method most meaningful to them